A similar type of machine used for reducing wood and green waste material is disclosed in the commonly owned U.S. Ser. No. 10/225,714. The machine of that patent utilizes a rotor with projections referred to as hammers. Wood materials are conveyed along a path toward the rotating rotor and are first compressed by a compression roller which directs the material against the rotor. The rotor rotates to direct the material up and over the rotor into an overlying fixed anvil or anvil bar located in close proximity to the hammers and thereby to break the materials into smaller sized chunks of material. The thereby reduced material is forced along and through a series of screens which further reduce the material size. The material is deposited on a conveyor and conveyed to a staging area for recycling, e.g., as groundcover.
One further aspect of note for the machine as described is the provision of a safety release. In the event that a non-wood material, such as a chunk of iron, gets mixed in with the wood and is directed into the rotor and thereafter against the anvil, the anvil is designed to pivot open upon the breaking of a shear pin resulting from the increased impact of the iron mass against the anvil. The operation is closed down and the shear pin is replaced. While the operation is thus interrupted, such occurrences are not frequent and the major components of the apparatus are safeguarded as a result of the shear pin breakage and pivotal mounting of the anvil.
Use of the same machine is not satisfactory for reducing materials, e.g., resulting from structural demolition. Whereas a non-reducible item is but a rare occurrence for reducing wood materials, it is a common occurrence among structural demolition, and operation interruptions of the kind where replacing shear pins for such occurrences is undesirable.